Start planning now for an enjoyable summer

While it’s true that the weather is warm, it’s not yet sweltering. That means it’s a good time to have your car’s air conditioning system thoroughly inspected and serviced, before it’s desperately needed. Most cars, especially if they’re about five years old or newer, will greet the heat with a reliable blast of cold air, but what should you do if yours blows warm air, or no air at all?

If your air conditioner isn’t working at all, the fix will require some detective work. Sometimes it’s a simple matter of a low refrigerant charge or a switch or sensor needing replacement. Air conditioning systems are pressurized, and there are sensors to detect when things are out of whack. If something’s not right, the AC will protect itself and its expensive components by re
fusing to engage. Warm air from the vents when you’re asking for cold means it is time to have your dealer’s service department diagnose the trouble.

Your dealer’s service department has technicians who are most familiar with your vehicle and its systems, plus the information, tools and support of the manufacturer. They’ll know common trouble areas, if any, and, more important, the best way to fix them.

The first thing your technician will check for is leaks. If there’s not enough refrigerant, it had to go somewhere. Sometimes an initial inspection will turn up a big leak, like a perforated hose or pipe, but other times it can be harder to track down. Tricky leaks may require a recharge of the system and the addition of a dye that shows up under a black light.

If there are no obviously compromised components, a check of the operating pressures is in order. There’s a special set of gauges technicians will hook up to the high- and low-pressure portions of the system. This will tell them the amount of charge in the system and whether pressures change properly while the air conditioning is running. Because refrigerant molecules are very small, some does escape past the seals in the system, so a low refrigerant condition could just be due to the age of the car. In that case, a simple topping-off will get you comfortable again.

Even if your AC isn’t completely inoperable, a low refrigerant condition will deteriorate performance. Contrary to what you might think, if there’s not enough refrigerant in the system, the AC will actually cool too much, which will cause some parts of the system to freeze, triggering a sensor to shut the AC down until it thaws.

Larger system faults involving critical components, like a compressor with bad seals or failing bearings, or an evaporator core that’s leaking, require more involved repairs. The compressor is under the hood, driven by the engine. It is subjected to a lot of heat and mechanical stress. The evaporator is usually inside the cabin, inside the dashboard. It absorbs the heat from the interior air, and is kind of like a specialized radiator, made up of small tubing and fins. Parts like these can be labour-intensive to remove and replace.

To open the AC system, a technician will first connect a machine that removes any refrigerant from the system so none escapes to the atmosphere when the system is disassembled. Once the system is repaired, a vacuum pump will be used to make sure there’s no moisture within the plumbing and there are no leaking seals. If the system holds a vacuum, it is then re-charged with the correct amount of refrigerant, and your cool will be restored.

It’s only going to get hotter as the summer wears on, so have your air conditioning system tested, and repaired if needed, while you can still comfortably cruise with the windows down.